| 摘要 |
PROBLEM TO BE SOLVED: To provide ferritic spheroidal graphite cast iron in which high temperature strength and thermal fatigue resistance are further improved, and also, machinability is improved, and a method for manufacturing the same. SOLUTION: The ferritic spheroidal graphite cast iron has a composition comprising, by mass, 3.0 to 3.6% C, 4.0 to 4.4% Si, 0.3 to 0.7% Mo, 0.2 to 0.5% V and 0.09 to 1.1% W, and the balance Fe with inevitable impurities. The cast iron is produced, after the casting of the ferritic spheroidal graphite cast iron, by performing holding at a temperature from an Ac1 transformation starting temperature-70°C to an Ac1 transformation starting temperature for 0.2 to 2 hr, and thereafter gradually cooling the same to an Ar1 transformation finishing temperature or below at a cooling rate of air cooling of≤5°C/min. COPYRIGHT: (C)2011,JPO&INPIT |
